JP-A-2000-105203 (Patent Document 1) describes that a spatial filter blocks light refracted from a repeating pattern of a circuit pattern (that is a high-density repeating pattern and is not a repeating die and the like) located on a substrate to be inspected in order to inspect a foreign material or defect, which occurs during a process of manufacturing an LSI or a liquid crystal substrate. In addition, JP-A-2000-105203 describes that a technique for calculating a variation on the basis of a signal detected from a location at which the same circuit pattern is originally formed or a signal detected from a region located near the location, setting a judgment criterion (threshold) on the basis of the calculated variation, and extracting a signal indicating a defect such as a foreign material in a defect determination process.
In addition, JP-A-H10-90192 (Patent Document 2) describes a defect inspection method and a defect inspection device, which causes at least one of given inspection responses of a second pattern to be referenced in order to search a defect present at a point (to be inspected) located on a first pattern that has the same design as the second pattern and is located on a sample. JP-A-H10-90192 also describes the following technique. For the inspection, it is important to use points (to be observed) that correspond to each other and are located on the first and second patterns on the sample. The search is performed at least one time to generate at least two inspection responses. The two inspection responses (response signals from a dark field and a bright field are representative inspection responses) are separately detected by a photoelectric method and separately compared so that differential signals between the first and second patterns are individually formed. Specifically, first and second responses are detected from the first pattern. The detection results are compared with two responses detected from corresponding points (to be inspected) of the second pattern. As a result, the first and second differential signals of the responses are formed.
The individually formed differential signals are subjected to data processing in order to determine a unified list of defects of the first pattern. Specifically, the first and second differential signals are collectively subjected to data processing, and the unified list of defects of the first pattern can be determined. After that, the first pattern defect list may be subjected to data processing. Then, a known, neglectable and false defect that can be viewed on the sample surface is extracted and removed. The known, neglectable and false defect is provided to a user as a reference. In addition, a various types of search for inspection are performed to increase inspection responses, and two or more optical responses are obtained from the sample and processed. Thus, the inspection accuracy is further improved. In addition, a photoelectric detector is arranged on the back side of a transparent sample, and inspection responses are collected using transmitted light. Thus, the accuracy of the aforementioned pattern defect list can be improved. In addition, a defect that is concealed in the sample can be searched.